1. Technical Field
The present invention relates to integrated circuits in general, and, in particular, to resistors within integrated circuits. Still more particularly, the present invention relates to a method for manufacturing a self-compensating resistor within an integrated circuit.
2. Description of Related Art
It is often desirable for all resistors within an integrated circuit device to have an identical target resistance. However, most process controls for manufacturing resistors on a wafer fall short of the above-mentioned goal. As a result, the resistances of various resistors tend to vary from chip to chip on the same wafer, and from wafer to wafer on the same lot.
The industry standard specifications for demanding resistance uniformity of all resistors on a wafer are getting progressively tighter over the years. In order to meet the industry standard specifications, there are three options that exist today for insuring identical resistances on all resistors on a wafer, and they are:
1. manufacture extra resistors on a wafer for subsequent sorting;
2. use laser ablations; and
3. design in-circuit active impedance control to compensate for process variability.
However, each of the above-mentioned three options has its own problem. The first option is relatively expensive and is not consistent with manufacturing techniques. The second option is not consistent with the standard complementary metal oxide semiconductor (CMOS) process flow. The third option takes up space, increases complexity, and may lead to overall performance degradation.
Consequently, it would be desirable to provide an improved method for manufacturing resistors having an uniform resistance.